The purpose of this research project is to develop a simple method for the purification of erythropoietin from crude extracts of urine which does not require large quantites of starting material. To this end, we are evaluating the technique of affinity chromatography using adsorbents such as lectins, antibodies, enzymes and substituted and unsubstituted hydrocarbon chains which are immobilized on agarose. Adsorbents which are found to quantitatively but reversibly bind erythropoietin in preference to other proteins in crude urine extracts, will be used in conjunction with conventional separation procedures such as gel filtration and ion exchange chromatography to purify the hormone to homogeneity.